This invention generally relates to controlling a visual screen display to reduce the amount of power consumed when displaying an image. More particularly, this invention relates to a method of selectively energizing screen pixels to realize a desired screen brightness while saving power and reducing variations in the amount of energy used to power the display screen.
A variety of visual screen displays are useful for displaying electrically generated images. A variety of factors must be accounted for to produce a desirable display. One of those factors is the brightness or shading level on the screen. One way of controlling screen shading is known as frame modulation.
Frame modulation techniques have several advantages, however, they do not always optimize power consumption. More recently, visual displays have been used with portable devices, which necessarily are powered by a battery or a similar portable energy source. In such situations it is especially important to control power consumption by a display screen to maximize battery life. Conventional frame modulation techniques typically included a static method of sequencing for energizing screen pixels to realize various brightness levels on the screen. Such static sequencing techniques do not efficiently utilize limited battery power. Therefore, there is a need for more efficient control of power consumption in a screen display, especially where frame modulation techniques are used to realize varying brightness levels.